extract a column of text

[-= JB =-]

my Thanks to Richard and Bjornke for the speedy replies.

-=>JB<=-



On Sep 3, 2008, at 4:27 PM, Richard Gaskin wrote:

> -= JB =- wrote:
>> What is the easiest way to extract a column of text from a variable.
>> For instance if I have a variable that has 200 lines with 12 items
>> in each line and I want to extract all 200 lines of item 4.
>> I have seen it done somewhere which allows me to either remove
>> a column or extract a column but I do not remembe
>
>
> I've benchmarked many methods, so far the simplest is also the  
> fastest:
>
> put GetCol( tData, 4) into tMyCol
> -- where tData is simply tab-delimited text,
> -- and 4 is the column number you want to get
>
>
> function GetCol pData, pCol
>   set the itemdel to tab
>   put empty into tReturnList
>   repeat for each line tLine in pData
>      put item pCol of tLine &cr after tReturnList
>   end repeat
>   delete last char of tReturnList -- trailing CR
>   return tReturnList
> end GetCol
>
>
> On my 2.16GHz machine, that performs at the rate of about 520,000  
> lines per second.  Hopefully it'll be fast enough for your needs. :)
>
> Splitting it into an array is very useful if you then need to go  
> back and extract a large number of specific elements.  But for  
> sequential processing of an entire data set, I've not yet found a  
> method which benchmarks faster than "repeat for each".
>
> -- 
>  Richard Gaskin
>  Managing Editor, revJournal
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